Kinetic Model for the Oxidative Degradation of Aqueous p-Nitrophenol by Fenton’s Reagent

Abstract

This work investigates the oxidative degradation of p-Nitrophenol (PNP) pollutant in aqueous solution using an environmentally friendly advanced chemical oxidation (Fenton’s) process. Degradation experiments of PNP present in aqueous solutions in the concentration range between 3.597 x 10^-3 moles/L (500 ppm) and 7.188 x 10^-3 moles/L (1000 ppm) were carried out in a batch rector. This work describes a mechanistic study for the reaction kinetics between the PNP and hydroxyl (^•OH) radical. A model of mechanistic study was planned for degradation of an aqueous PNP in Fenton’s process and that model was used for the calculation of rate constant of the reaction showing the influence of hydroxyl radicals on PNP degradation. Around 96.80 % of degradation was achieved after 60 min of reaction time [700 ppm of PNP concentration, 0.1006 moles/L H₂O₂, 1.798 x 10^-3 moles/L of Fe²⁺ catalyst and pH 3]. Our main purpose was to determine the reaction rate constant between PNP and the hydroxyl radical. The reaction rate constant for the reaction of PNP removal with ^•OH radicals is estimated as 2.76 x 10¹⁰ L/mole-s.